US6144734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-pass filters for splitterless pots and data transmission
Assignee: Siemens Communications Inc
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Filing: 1998-06-30
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Granted: 2000-11-07
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Expires: 2018-06-30
Abstract
Abstract A transmission system includes a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f1 and for data service occupying the frequency spectrum above another predetermined frequency f3, where f3 is substantially higher than f1, a plurality of telephone sets at said receiving station connected in parallel with one another to the transmission path, and where each of the telephone sets has an on-hook state which presents a substantially infinite resistance to the transmission path and an off-hook state which presents a predetermined resistance R to the transmission path. A plurality of separate and substantially identical multi-pole low-pass filters are provided for connection between the transmission path and respective ones of the telephone sets, where each of the low-pass filters has a -3 dB frequency f2 which lies between f1 and f3, and a characteristic impedance of substantially (n*R), where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop at frequencies below f1 because of resonances that occur between f1 and f2 with at least one but less than all of said telephone sets off-hook.
Inventors
- 👤 Robert H. Beeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:15
CPC Classifications
H; H04; H04M; H04M11/00; H04M11/06; H04M11/062
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
210 words
In a transmission system which includes a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f 1 and for data service occupying the frequency spectrum above another predetermined frequency f 3 , where f 3 is substantially higher than f 1 , a plurality of telephone sets at said receiving station connected in parallel with one another to said transmission path, and where each of said telephone sets has an on-hook state which presents a substantially infinite resistance to said transmission path and an off-hook state which presents a predetermined resistance R to said transmission path: a plurality of separate and substantially identical multi-pole low-pass filters connectable between said transmission path and respective ones of said telephone sets, where each of said low-pass filters has a -3 dB frequency f 2 which lies between f 1 and f 3 , and a characteristic impedance of substantially (n*R), where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop at frequencies below f 1 because of resonances that occur between f 1 and f 2 with at least one but less than all of said telephone sets off-hook.
Claim 2
Dependent Claim
210 words
In a transmission system which includes a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f 1 and for data service occupying the frequency spectrum above another predetermined frequency f 3 , where f 3 is substantially higher than f 1 , a plurality of telephone sets at said receiving station connected in parallel with one another to said transmission path, and where each of said telephone sets has an on-hook state which presents a substantially infinite resistance to said transmission path and an off-hook state which presents a predetermined resistance R to said transmission path: a plurality of separate and substantially identical multi-pole low-pass filters connectable between said transmission path and respective ones of said telephone sets, where each of said low-pass filters has a -3 dB frequency f 2 which lies between f 1 and f 3 , and a characteristic impedance of substantially (n*R), where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop at frequencies below f 1 because of resonances that occur between f 1 and f 2 with at least one but less than all of said telephone sets off-hook.
Claim 3
Dependent Claim
40 words
The filters of claim 1 in which each of said filters has an even number of poles, an inductive side for connection to said transmission path, and a capacitive side for connection to a respective one of said telephone sets.
Claim 4
Dependent Claim
51 words
The filters of claim 1 in which each of said filters has an odd number of poles, an inductive side for connection to said transmission path, an inductive side for connection to a respective one of said telephone sets, and capacitor containing elements interior to the filter between said inductive sides.
Claim 5
Dependent Claim
53 words
The filters of claim 1 in which, in each filter, when compared to the same filter designed for a characteristic impedance of 1 ohm resistance and a -3 dB frequency of 1 radian per second, all inductors are scaled by the expression: (n*R)/(2*f.sub.2) and all capacitors are scaled by the expression: 1/(2π*f.sub.2 *n*R).
Claim 6
Dependent Claim
36 words
The filters of claim 4 in which each of said filters is an m pole Butterworth filter, where m is an integer greater than 1, and each of said filters is balanced with respect to ground.
Claim 7
Dependent Claim
27 words
The filters of claim 5 in which each of said filters is a 2-pole Butterworth filter, and each of said filters is balanced with respect to ground.
Claim 8
Dependent Claim
40 words
The filters of claim 4 in which each of said filters has an even number of poles, an inductive side for connection to said transmission path, and a capacitive side for connection to a respective one of said telephone sets.
Claim 9
Dependent Claim
51 words
The filters of claim 4 in which each of said filters has an odd number of poles, an inductive side for connection to said transmission path, an inductive side for connection to a respective one of said telephone sets, and capacitor containing elements interior to the filter between said inductive sides.
Claim 10
Dependent Claim
32 words
The filters of claim 4 in which f 1 is substantially equal to 4 kHz, f 2 is substantially equal to 10 kHz, and f 3 is substantially equal to 24 kHz.
Claim 11
Dependent Claim
222 words
Filter apparatus for use in a transmission system which comprises a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f 1 and for data service occupying the frequency spectrum above another predetermined frequency f 3 , where f 3 is substantially higher than f 1 , and a plurality of telephone sets at said receiving station connected in parallel with one another to said transmission path, where each of said telephone sets has an on-hook state which presents a substantially infinite resistance to said transmission path and an off-hook state which presents a predetermined resistance R to said transmission path, said filter apparatus comprising: a plurality of separate and substantially identical multi-pole low-pass filters for connection between said transmission path and respective ones of said telephone sets, where each of said low-pass filters has a -3 dB frequency f 2 which lies between f 1 and f 3 , and a characteristic impedance of substantially (n*R), and where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop in said filters at frequencies below f 1 because of resonances occurring between f 1 and f 2 with at least one but less than all of said telephone sets off-hook.
Claim 12
Dependent Claim
222 words
Filter apparatus for use in a transmission system which comprises a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f 1 and for data service occupying the frequency spectrum above another predetermined frequency f 3 , where f 3 is substantially higher than f 1 , and a plurality of telephone sets at said receiving station connected in parallel with one another to said transmission path, where each of said telephone sets has an on-hook state which presents a substantially infinite resistance to said transmission path and an off-hook state which presents a predetermined resistance R to said transmission path, said filter apparatus comprising: a plurality of separate and substantially identical multi-pole low-pass filters for connection between said transmission path and respective ones of said telephone sets, where each of said low-pass filters has a -3 dB frequency f 2 which lies between f 1 and f 3 , and a characteristic impedance of substantially (n*R), and where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop in said filters at frequencies below f 1 because of resonances occurring between f 1 and f 2 with at least one but less than all of said telephone sets off-hook.
Claim 13
Dependent Claim
41 words
The filter apparatus of claim 10 in which each of said filters has an even number of poles, an inductive side for connection to said transmission path, and a capacitive side for connection to a respective one of said telephone sets.
Claim 14
Dependent Claim
52 words
The filter apparatus of claim 10 in which each of said filters has an odd number of poles, an inductive side for connection to said transmission path, an inductive side for connection to a respective one of said telephone sets, and capacitor containing elements interior to the filter between said inductive sides.
Claim 15
Dependent Claim
54 words
The filter apparatus of claim 10 in which, in each filter, when compared to the same filter designed for a characteristic impedance of 1 ohm resistance and a -3 dB frequency of 1 radian per second, all inductors are scaled by the expression: (n*R)/(2π*f.sub.2) and all capacitors are scaled by the expression: 1/(2π*f.sub.2 *n*R).
Claim 16
Dependent Claim
37 words
The filter apparatus of claim 13 in which each of said filters is an m pole Butterworth filter, where m is an integer greater than 1, and each of said filters is balanced with respect to ground.
Claim 17
Dependent Claim
28 words
The filter apparatus of claim 14 in which each of said filters is a 2-pole Butterworth filter, and each of said filters is balanced with respect to ground.
Claim 18
Dependent Claim
41 words
The filter apparatus of claim 13 in which each of said filters has an even number of poles, an inductive side for connection to said transmission path, and a capacitive side for connection to a respective one of said telephone sets.
Claim 19
Dependent Claim
52 words
The filter apparatus of claim 13 in which each of said filters has an odd number of poles, an inductive side for connection to said transmission path, an inductive side for connection to a respective one of said telephone sets, and capacitor containing elements interior to the filter between said inductive sides.
Claim 20
Dependent Claim
33 words
The filter apparatus of claim 13 in which f 1 is substantially equal to 4 kHz, f 2 is substantially equal to 10 kHz, and f 3 is substantially equal to 24 kHz.
Claim 21
Dependent Claim
213 words
A transmission system comprising: a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f 1 and for data service occupying the frequency spectrum above another predetermined frequency f 3 , where f 3 is substantially higher than f 1 , and a plurality of telephone sets at said receiving station connected in parallel with one another to said transmission path, where each of said telephone sets has an on-hook state which presents a substantially infinite resistance to said transmission path and an off-hook state which presents a predetermined resistance R to said transmission path; and a plurality of separate and substantially identical multi-pole low-pass filters for connection between said transmission path and respective ones of said telephone sets, where each of said low-pass filters has a -3 dB frequency f 2 which lies between f 1 and f 3 , and a characteristic impedance of substantially (n*R), and where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop in said filters at frequencies below f 1 because of resonances occurring between f 1 and f 2 with at least one but less than all of said telephone sets off-hook.
Claim 22
Dependent Claim
213 words
A transmission system comprising: a transmission path from a transmitting station to a receiving station for both voice telephone service occupying the frequency spectrum below a predetermined frequency f 1 and for data service occupying the frequency spectrum above another predetermined frequency f 3 , where f 3 is substantially higher than f 1 , and a plurality of telephone sets at said receiving station connected in parallel with one another to said transmission path, where each of said telephone sets has an on-hook state which presents a substantially infinite resistance to said transmission path and an off-hook state which presents a predetermined resistance R to said transmission path; and a plurality of separate and substantially identical multi-pole low-pass filters for connection between said transmission path and respective ones of said telephone sets, where each of said low-pass filters has a -3 dB frequency f 2 which lies between f 1 and f 3 , and a characteristic impedance of substantially (n*R), and where n is a number equal to at least 2.4, thereby reducing the effect of low impedances that develop in said filters at frequencies below f 1 because of resonances occurring between f 1 and f 2 with at least one but less than all of said telephone sets off-hook.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-11-07 | 2004-05-08 | 2004-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-11-07 | 2008-05-08 | 2008-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-11-07 | 2012-05-08 | 2012-11-07 | $7700.00 | Window Closed / Lapsed |